1. Field of the Invention
The present invention is a web centerline locating system, and which particularly allows for a quick and positive establishment of the vertical location of the center of a web thickness. The present invention allows rapid determination of a reference point for drilling holes in the flanges of such structural shapes as I-beams, by ensuring that the flange holes will be accurately gaged on either side of the web between the flanges. The present invention includes the web centerline locating system in combination with a coordinated drilling assembly, wherein a horizontal drill assembly may be accurately placed for drilling holes into vertical flange surfaces of structural members, with the holes being accurately gaged on either side of the horizontally extending web of the member, regardless of manufacturing errors in the structural member itself.
2. Description of Prior Art
There is not known to be a prior art web centerline locating system which employs two opposed probes for contacting the top and bottom surfaces, respectively, wherein the vertical position of the centerline of the web is mechanically referenced through a bellis device. From a search of prior art, applicant has discovered the prior United States patents, as follows: U.S. Pat. Nos.: KRIVACS; 1,410,196, BETHEN; 2,348,878, KEYS; 2,660,802, SLAMAR; 3,065,415, ERTMAN; 3,562,918, LEMELSON; 3,805,393.
The early patent to Krivacs illustrates one form of center gage where the distance between pads, 10, will be divided and indicated by a pointer, 1. As such, Krivacs illustrates the principle of mechanically determining a centerline between two measured points, although he does not provide a system for indicating and referencing a centerline to an external standard, as is particularly taught herein.
The patent to Behen illustrates another form of centerline locating device, per se, one which is structurally adapted for determining the centerline of a square surface by elements positioned at the intersection of the diagonals of the square to be centered. As such, Behen simply further illustrates a device for mechanically dividing distances between particular points.
The patent to Keys is categorically pertinent because he illustrates a marking gage to locate the centerline of the web upon the flanges of I-beams, and the like. Keys' device is representative of the prior art approach of manually scribing a line, directly upon the flange of the I-beam. In contrast, with the present invention an accurate vertical position for the centerline of a web may be externally referenced by a simply probing, without requirement of physically marking the flange at a centerline position. The Keys marking gage requires that the distance between the scribe, 3, and the screws, 10, be set for the centerline of a given web, 1, so that any variation in web thickness will not be accounted for during the scribing operation. In contrast, the present invention accurately determines a centerline for any given web thickness, without the necessity of knowing or sensing what the value of the thickness is. Additionally, the centerline location is always referenced to an external, vertical standard.
The patent to Slamar illustrates an electro -- mechanical device for determining variations in the thickness of the web of an I-beam, for example, as it travels over a conveyor. Slamar's device is, therefore, concerned with monitoring thickness variations in structural steel dimensions, and not with referencing the location of the centerline of any thickness to an external standard, so that a drill assembly may be accurately referenced with respect to that vertical location. Slamar is pertinent insofar as he illustrates that the position of a rack, 7, may be translated, through pinion, B, by an electric pulse circuit. The present invention, in one embodiment, may similarly employ an encoder to generate electrical pulses, in response to the vertical position of an indicator rack, so that such an electrical single output can be processed in any number of ways to represent the vertical location of the centerline of the web.
The patent to Ertman illustrates a device for determining both dimensional accuracy and symmetry deviation of any part of a structural member, through a plurality of contacts between probes and surfaces on the structural member. For example, the probes P-5 and P-6, shown in FIGS. 2A and 8, are connected to transducers, to produce signals which are then electronically processed to indicate, for example, that deviation of the thickness of a web from a derived horizontal centerline, as shown at B--B in FIG. 8. In contrast, the present invention requires only a bellis assembly to mechanically derive the vertical location of the centerline of the web, with that vertical location being calibrated to an external standard. This feature is significant in the present invention, because the vertical location of the centerline of the web may then be used to easily position a horizontal drill assembly. Thereby, the holes drilled into the flange will be accurately referred to the centerline of the web at that position on the structural member. The problems addressed by the present invention require simply the establishing of an external reference point for the location of the centerline of the web in a structural member, and the present invention simply and efficiently creates such an external reference to the vertical location of the web centerline, without the need for involved electrical or mechanical subsystems.
The patent to Lemelson is electro-mechanical device for primarily determining dimensions of a given member, and not with simply establishing the vertical location of the centerline of an horizontally disposed web. Lemelson is considered illustrative of an automatic caliper wherein electrical signals are generated from the positions of mechanical probes, hence, he illustrates various logic subsystems for translating mechanical movement into electrical outputs. By contrast, the present invention is specific to a device for mechanically determining the physical location of the centerline in a horizontal member, without regard to the actual dimension of the centerline. The present invention allows for a centerline to be quickly and efficiently referenced to an external standard, without the need of initially determining what the thickness of a web is, at any given point along a structural member. Hence, the present invention is structurally adapted for centerline location determination, and does not also require the monitoring of any particular dimension of a structural steel member for conformance to tolerances.